Bimetallic MOF-based catalysts with enhanced activity for electrochemical hydrogen evolution in acid and alkaline electrolytes

Abstract

A family of MOF-based bimetallic electrocatalysts M_xNi_1−x-NKU-100 (M = Mn, Fe, Co, Cu, Zn) were synthesized for the hydrogen evolution reaction (HER). The modulation of the bimetallic centers significantly influence the electrocatalytic HER activities. In acidic electrolytes, Cu_xNi_1−x-NKU-100 exhibit enhanced electrocatalytic performance. Cu_0.22Ni_0.78-NKU-100 achieved 10 mA cm⁻² current density at 224 mV overpotential with a 126 mV dec⁻¹ Tafel slope. In alkaline electrolytes, the Fe_xNi_1−x-NKU-100 catalysts exhibit better electrocatalytic HER activities compared with other M_xNi_1−x-NKU-100. Fe_0.24Ni_0.76-NKU-100 achieved 10 mA cm⁻² current density at 249 mV overpotential with a Tafel slope of 137 mV dec⁻¹. The synergistic effects of the bimetallic electrocatalysts in acidic and alkaline electrolytes are discussed in detail.